And if BA HR created a 'blacklist' they would be leaving themselves open to a multitude of legal attacks costing millions.
If you work for BA already and are refused an internal application because you trained under the modular route you have nothing to fear by taking the firm to tribunal. Hundreds of BA staff are at tribunal with the company every year.
In fact I just read in the Telegraph of a 26yr old female FO with 4 years service who is taking BA to tribunal over their refusal to offer her a 50% roster.
Cheers
WWW
ps There is no industry blacklist or secret society of Chief Pilots. Its all a myth put about to scare young pilots to bed.